Treatment of potash ores



United States Patent 9 T TREATMENT OF POTASH ORES Edmund A. Schoeld andJohn Melvin Fritschy, Carlsbad, N. Mex., assignors to Potash Company ofAmerica, Carlsbad, N. Mex., a corporation of Colorado No Drawing. FiledMay 7, 1953, Ser. No. 353,665 1 Claim. (Cl. 209-166) This inventionrelates and more particularly of potassium chloride in the processes asa a flotation modifier.

In general, potash ores contain potassium chloride and sodium chloridein varying proportions, as well as smaller amounts of other salt andinsoluble matter such as clay. Commercially, the potassium chloride isrecovered from the sodium chloride and other impurities of the ore by afroth flotation process. In flotation, finely ground potash ore is mixedwith a saturated solution of the ore, and by adding collection,conditioning, levitation, frothing, etc. agents the sodium chloride isfloated away from the potassium chloride-or vice versa. Variouscombinations of processes and agents are well known in the art oftreating potash ores, and we have now discovered that very small amountsof guar flour introduced into the separation proc esses unexpectedly anduniquely aids in the separation. In the flotation phase of floating onemajor constituent of ore from the other major constituent, very smallamounts of guar added to the pulp improve the metallurgical performance.Starch has been used as a froth modifier in the prior art with somesuccess, but we have now discovered that guar flour is effective as aflotation modifier in amounts of down to one-tenth or less of theamounts of starch required in the prior art processes. This uniquediscovery not only greatly saves material, but increases the efliciencyof the process.

It is an object of the present invention to provide an improved frothflotation for treating potash ores. Another object of the invention isto provide a new and eflicient froth modifier for flotation processes.

A further object of the invention is to provide a new and eflicientflocculating and floating agent for insoluble impurities in the frothflotation of potash ores.

Another object of the present invention is to provide a new and uniquefroth modifier for flotation processes of treating potash ores, which isequally effective in the flotation of either potassium chloride orsodium chloride.

These and other objects will be apparent by reference to the followingdescription.

Small amounts of guar flour added to a potash ore pulp during flotationimproves the metallurgical performance, giving a lower grade of tailingsand a higher grade of con centrates. In speaking of the grade, theproportion of potassium chloride is the reference. The addition of thesmall amounts of guar, aid the separation of the components of thepotash ore, whether either the potassium chloride or the sodium chlorideis floated. The use of guar is an aid to the flotation with the use ofseveral of the common flotation reagents, including soap, soap-likereagents, alkyl amines, etc.

Although the guar shows somewhat different behavior with the differentreagents the essential action is the same. In soap flotation, forexample, the water insoluble matter tends to float and the guar assistsby reducing the number of particles which makes the froth easier to tothe treatment of potash ores, to flotation processes for recoveryflocculating agent, a clarifier, and

from potash ores using guar flour 2,952,358 Patented Sept. 13, 1960handle. Extremely fine particles tend to build up a permanent froth, butthe guar flocculates these fine particles to prevent the building ofsuch a permanent froth. Further, the flocculation assists in the actualseparation. In amine flotation the insolubles tend to be floated quitevigorously by the amine. The amine is absorbed by the insoluble mattermore readily than by the potassium chloride, which of course uses up theamine reagent. Normally the clay must be removed or inactivated toenable the amine to be absorbed and float the minerals of value. The useof guar protects the clay from excessive absorption of the reagent, andimproves the metallurgical performance of the flotation.

CLARIFICATION WITH GUAR In small amounts, guar is an excellentclarifier, and is.

Table I.-Inches of clear liquid above suspended solids Reagent asLbs/Ton None 0.52 Starch 0.008 Guar Time Elapsed, min:

1. none 1 ,6 2

FLOTATION WITH GUAR MO'DIFIER The flotation tests were conducted in alaboratory model flotation machine which uses 200 grams of ore in abatch. Ore was prepared by grinding a screening through 28 mesh screen,then slurried in brine and placed in the machine. The modifier was addedand after preliminary agitation, the flotation reagents were added andflotation continued until complete.

In flotation, 0.1 to 0.5 pound of guar per ton of ore shows excellentmetallurgical performance. The guar is efiective in the flotation ofsodium chloride as well as of potassium chloride. In the flotation ofsalt, guar flocculates the extremely fine water insoluble clay, whichotherwise collects in the bubbles and makes a very stable froth. Thefollowing tables show the comparison of guar to starch, and thequantities of each.

Table II.Fl0tati0n with soap reagent [Brine-containing lead saltequivalent to 2 grams lead per liter. Flotation reagents in order ofaddition (half in tails flotation, half in middlings flotation).Creoylic acid- .21 lbs/ton. Soap of mixed aliphatic acid used incommercial operation 1.4 lbs/ton] Starch Guar 0.1 Modifier None 0.5lbs/Ton lbs/Ton Comparative Depth of Froth 1.0 0. 62 0.69 K0 inConcentrate -percent 72. 4 81. 2 82.1 K01 in Mids 7. G S. 8 10.3 K01 inTails 2.5 4.1 4.1 Insolubles in Gene 41.0 35.0 23.0 Insolubles in Tailsand Mids 59. 0 65.0 77.0

This table shows the amount of guar to be a better flotation modifierthan starch. The guar upgrades the concentrate, showing excellentmetallurgical performance. The use of guar increases efficiency morethan is evidenced by the tables, as it not only improves themetallurgical performance it also improves the handling of the tailingsand the concentrates. Soap reagent when used herein includes true soaps,fatty acids, etc. which produce the same effect as soap in the flotationof the potash ore.

In the alkyl amine flotation, guar gives very good metallurgicalperformance whether the insoluble matter is present or not. Normally, inamine flotation the insoluble slime must be removed or inactivated toenable the amine to be absorbed on and float potassium chloride. Guarprevents absorption of amine on the slimes, so excessive amounts ofreagent are not required. The following table shows the comparison ofusing starch and guar in the flotation.

4 separations of the soluble constituents of the ore, which comprisesforming a pulp of the ore by introducing finely divided sylvinite oreinto a saturated solution of the ore containing approximately two gramsof soluble lead per liter, introducing such pulp into a flotation stagein each brine cycle, introducing guar flour in the amount of about 0.1to 0.5 pound per ton of ore into said flotation stage for flocculatingfine particles of water-insoluble clay contained in said pulp so as toproduce a less stable froth at the flotation stage, directing theseparated prod nets of flotation to subsequent treatment stages, and

Table [HQ-Flotation tests with amine reagent [Preliminary agitation: 2minutes.

Flotation reagents: pine oil or methyl isobutyl carbinol 1 drop in firstfloat,

1 drop in cleaning octadecylamine acetate added in 2 stages in firstfloat] Modifier lbs/Ton Starch 2 Sti1r5ch Starch 1 Guar 0.5 Guar 0.4Guar 0.3 Guar 0.2 None Amine lbs/Ton 0.36 0.32 0. 32 0.32 0.36 0. 360.36 0. 36 Percent KCl in 00110---- 1 90. 5 98.3 94.1 96.6 1 91.6 1 87.41 88.2 1 69.4 Percent K01 in Talls 1. 8 1. l3 8. 3 0. 89 1. 13 1. 42 2.83 35. 1 Recovery in Conc--.. 97. 4 96. 2 61.1 97. 8 98. 5 98. 1 96.016.0 Percent Insolubles loated 45 74 75 57 62 76 75 Percent Insolublesin Tails 55 26 43 38 24 25 Concentrates were not cleaned by refioating,and show higher grade on cleaning.

This table shows excellent metallurgical performance for guar modifieras compared to much larger amounts of starch. The flotation with theamine reagent is effective in amounts down to about 0.1 lb. per ton forreducing reagent absorption and inducing adequate flocculation. The guarimproves metallurgical performance, giving lower grade of tailings and ahigher grade of concentrates than possible without a flotation modifier.

The examples and description above are for illustrating the principlesof the invention, but should not be construed to limit the scopethereof. Guar is valuable in flotation in more aspects than shown, butthere is no intention to limit the invention to the precise detailsdisclosed except in so far as defined by the appended claim.

We claim:

A process for the treatment of sylvinite ores, in which a brine of theore is recycled through a succession of References Cited in the file ofthis patent OTHER REFERENCES Journal of the American Chemical Society,volume 70, June 1948, pages 2249-52.

Chemical Industries, volume 62, January 1948, pages -61.

